That's nice that you'd like to share the skills that have helped you with your kids.

As long as they are adults though, and of course unless they have a psychiatric condition which prevents them from making decisions about their own life, you can't get them in therapy without their agreement legally. You could try to explain how DBT has helped you and maybe that will convince them, but you can't take them to therapy as you would do with a minor. Sometimes it takes people a while to get into therapy and sometimes their path is just different - without knowing what specific issues your kids have, I generally think that there are more ways to overcome life's struggles. Many find therapy helpful, but many others prefer meditation, yoga, exercise, or something else. Trying to have someone else do it your way isn't necessarily going to help them much.

On the other hand, if your adult kids are in immediate danger, you can have them forcibly committed. Now, I'm not sure how to go from that to having them do DBT, because unfortunately where I live there isn't much psychotherapy going on at psych hospitals at all. But it can open up more options.